Remember how Shakespeare described Julius Caesar? “He doth bestride the narrow world like a Colossus,” the Bard said through the voice of the assassin Cassius, “and we petty men walk under his huge legs.”

That appraisal equally fits Lance Armstrong, another gent who came, saw and conquered Gaul. In a tumultuous decade of drug suspicions and convictions, of splendid victories and lamentable setbacks, Armstrong reigned supreme in the narrow world of bicycle racing.

His seven consecutive victories in the Tour de France, nearly all by robust margins, testify to his domination. He reeled them off from 1999, three years after he was diagnosed with testicular cancer that had spread to his head and chest, until 2005, when he retired.

Then, this year, at the age of 37, he returned to the sport and finished third in the Tour. He is already making much noise about his prospects next season.

Armstrong’s record outside the Tour de France is admittedly spotty. But the Tour is the greatest race in the sport and the Texan is a rider who won it year in, year out — breaking the previous record of five victories by such champions as Jacques Anquetil, Eddy Merckx, Bernard Hinault and Miguel Indurain.

Like Anquetil and Merckx, Armstrong also faced questions about the possible use of illegal performance-enhancing drugs. Unlike them, the Texan was never found guilty.

But, in the first decade of the new millennium, many other star riders did fail doping tests or, under pressure, admitted their guilt.

A low point occurred just days after Floyd Landis, another American, finished first in the 2006 Tour de France and was then found to have an excess of testosterone in his body. He was disqualified and eventually suspended for two years.

Another star who was suspended was Ivan Basso, an Italian who won the Giro d’Italia in 2006 and finished second in the 2005 Tour. Jan Ullrich of Germany, perennial second banana to Armstrong in the Tour, retired rather than answer questions about his links to the Operación Puerto drug ring in Spain.

Ullrich might have acted prematurely, since Spanish legal and sports officials have consistently blocked international efforts to air the 2006 case and name the names attached to more than 100 bags of blood found in a medical laboratory in Madrid.

And just this month, Spanish courts moved to close the case without divulging evidence. The same courts are resisting efforts to look at charges against Alejandro Valverde, a Spaniard and the rider ranked No. 2 in the world.

Outside Spain, the fight against doping has shown some gains. Not only dozens of lesser lights but also some stars have been disciplined.

Davide Rebellin, an Italian, was forced to return the silver medal he won in the Olympic road race in Beijing. Michael Rasmussen, a Dane, was ousted from the 2007 Tour while he was wearing the leader’s yellow jersey. Tyler Hamilton, an American and the winner of the Olympic time trial in 2004, was suspended for blood doping. Danilo di Luca, an Italian winner of the Giro d’Italia, was punished for his ties to a suspect doctor.

In 2004, David Millar, a Scot, had to forfeit his world time-trial championship when illegal drugs were found in his apartment. In 2007, Alexandre Vinokourov, the Kazakh leader of the Astana team, was expelled by the Tour for doping. In 2008, Bernhard Kohl, an Austrian who finished third in that year’s Tour and was its king of the mountains, was found guilty of doping, as was Stefan Schumacher, a German who won both long time trials in that race.